Steve Thomforde knows his trees.
After studying ecology for more than 10 years at the University of Wisconsin-Madison, he can spot the pokey limbs of an oak tree from about a mile away.
"I love oak trees," Thomforde says with a chuckle.
So much so that on Arbor Day, Thomforde helped about 200 volunteers plant 3,000 oaks in a 265-acre natural greenway along the border of Woodbury and Cottage Grove.
"We're some of these passionate people, 'Oh, I have to save the planet!' you know," said Thomforde, who is an ecologist and project manager for the nonprofit Great River Greening group, which organized the planting.
For nearly four hours, volunteers from age 4 and up trudged through tall-grassy prairie to several sites where they raked grass, shoveled soil and planted seedlings, which resembled twigs about the size of a pencil. The twigs came from a local nursery, which had cultivated hundreds of acorns that the group had gathered last year.
Of the 3,000 seedlings planted, the group hopes more than a third will grow, said Sandi Wagner, a volunteer supervisor who's been with the organization for two years.
The trees won't be visible for about 15 to 20 years, but those that take hold could live for hundreds of years, Wagner said.